eboggs_jkvl

I like your fix best! The LTs are your downfall for the CEL. When you tune, your friendly tuner will silence all those nasty CELs and you will have soooooo much fun with that SC! If I want to make my 50th anniversary this August, I must refrain from adding FI to my car for a while! My wife spells Forced Induction in a funny way, she sees it as DIVORCE!




Elmer

robert miller

Mine would also if she had known what I have spend on the other cars. She just like's to go shopping so I don't say nothing. I will be done with the c7 after this unless the spyder gears go out are the trans. Robert

jacob11379

So new here, sifting through threads, looking to get a louder exhuast. I have listened to the corsa extreme with double helix(and many others) and seem to like that sound. However at $2500-$2700 its a bit pricey if one can delete mufflers and put in an x-pipe to get close to same sound....

I happen to be buddies with an owner of an exhaust shop, I know he could likely build an x-pipe, axle back, and straight pipe while leaving NPP(I think thats what they are called) and stock exhaust tips...And probably do it for 3-$400...

So not to highjack thread but can someone quickly clarify if there is more that has to be done? is there something proprietary to that after market x-pipe?

kenownr

I have the Borla X-pipe install with the stock mufflers and NPP. Guys on here have deleted the mufflers and put on X-pipes without any problems that I've read about, although I understand it's quite loud that way and may draw LEO's in a quiet neighborhood.
Make sure you only remove the small "non-monitored" cats and not the other two as you will pull a CEL right away. Warranty issues? My service rep could care less about the X-pipe although he said to make sure you keep the original set-up as you may sell the car to an "emission" test state and it won't pass.

Rookienot1

I installed Borla X pipe on my C7 Z51 and love it! No codes, took about 45 minutes to do and sounds great. I have Borla S-type on my2016 SS Camaro and I love them too, but the stock NPP Exhaust sounded great so I thought Id try the X Pipe 1st. I find I really do not need the $2000 Borlas after all. No Codes, no problem and I love the sound!
I am still all over the board on CAI though. I have a LS3 2008 With K&N CAI and it really made a difference in my opinion. But the CAI's all get the air from the Right Fender area so it is not at all like my C6 that come cold from the front of the car! Any suggestions or input there would be welcomed...! Thanks in advance. Ron

JerryU

Your friend can save you even more money! All Vetts have had X pipes for years. just have him replace the secondary CATS, which is all the kits do!

Listen to the sound, it will be louder. You could eliminate the mufflers but then you would NOT have NPP. Consider getting a Mild to Wild kit (~$80) that allows you to open up the NPP exhaust when you want. Or if you don't mind a drone at highway speeds just pull the NPP fuse and you essentially have by-passed the mufflers!




Left two X-Pipe Kits, they essentially just eliminate the secondary CATs. Right OEM X-Pipe with secondary CATs. Just need to cut out CATs and weld in short pipes!

tyho

My car is a 2015 z51 M7 with the NPP valves. I installed AR mid length headers with the high flow cats and a Halltech carbon CAI.

I then replaced the OEM mufflers with B&B Bullets and deleted the NPP valves and removed the NPP actuators. Still no CEL.

I then installed a Borla catless x-pipe, so the secondary cats were removed as was the AFM valves and actuators. The car needed a tune at that point. the tune deleted the 1-4 skip shift and also deleted the 4 cylinder mode. The AFM actuators were replaced with the resistors I bought from a forum vendor. The resistors allow removal of the AFM without throwing a CEL.

The car is louder then stock but not by much when cruising. Gets loud when wot. Blast to drive.

Mobil 1

Has anyone tried gutting the back cats? Nobody including the dealer would know and it should sound close to what a Borla would sound like and be free to do.

rb185afm

Muffler delete with Corsa X pipe. Cold start and driving around with PDR. And third is PDR on track. It’s very loud!

JerryU

I had suggested that believing it would be easy for a DIY project that welding in a short pipe to replace the CATs. In fact still think it may be.


Could cut on the top side and even and "eagle eyed" inspector in CA would not see the secondary CATs were removed! (Reminded me of the State inspection with my first car, a '41 Ford Opera Coupe I stuffed in an Olds engine, added Buick taillights, decked so the license plate was mounted below the bumper (with light,) removed parking lights from the front fenders and installed small ones in the grill recess, glass pack mufflers, etc. No way those State inspectors would pass it with me driving! Had to have my Dad bring it and he was NOT a happy camper doing it!)

Could use a cut-off wheel as suggested in pic. Then a small ~$300 MIG welder with steel wire could be used to tack weld then finish weld the removed section back.

Someone posted they tried and it was difficult to remove the catalytic converter material (that material should be worth something as scrap or could make the wife a ring from the platinum! )
Another mentioned best to insert and weld in a pipe in the recess to get the best sound. Either way still looks easier than replacing the CATs with a short pipe unless you are a muffler shop.

badass1g

Gutting those secondary cats are a major PITA!!! Literally took me about 4-5 hrs to do the whole job (including time to go buy an air hammer). If I was to do it again, I would def have bought the borla! The sound barely got any louder. Maybe 5%.

Jshadow

I did the muffler delete and love the sound. Wondering if anyone has experience on how much of a sound increase you get from adding a borla/corsa xpipe to that system (which one is deeper?)

Also if anyone can answer how much louder would it be to do Long tubes w/muffler delete or are mid lengths just as good. I'm doing it more for sound then actual HP gains so for the money what do you all think is the best bet? Thanks

phalse

If I cut out the mufflers I'll probly be screwed when it comes time for smog inspection in the future. California sucks.